Certain large veins within the legs contain valves in the nature of check valves which prevent blood in these veins from settling into the lower regions of the legs and the feet. It is sometimes necessary or desirable to remove these valves, and this may occur in a medical procedure in which these veins are converted to arteries.
The valves can be removed using a valvulotome which comprises a catheter body which can be advanced through the vein of interest to a position adjacent the valve to be removed. The valvulotome includes a tool, which may comprise axially extending prongs, which can be advanced through the valve to disrupt and at least partially remove it. For this purpose, it is known to advance the catheter body with the tool fully retracted into the lumen of the catheter body to a position adjacent the valve and then extend the tool from the distal end of the catheter body so that it can perform its valve disrupting function.
To enable the physician to observe the procedure, the valvulotome may also include an endoscope. The endoscope includes an image-transmitting fiber extending through the catheter body and movable out the distal end of the catheter body under the control of the physician. Accordingly, the valvulotome may provide for independent axial adjustment in the positions of the tool and the distal end of the image-transmitting fiber.
One problem in use of the valvulotome is in positioning of the tool and the image-transmitting fiber. For example, during insertion of the catheter into the vein and the advance of the catheter through the vein, the tool and image-transmitting fiber would be entirely within the catheter body. During the medical procedure, the tool, and perhaps the distal end portion of the image-transmitting fiber, would be advanced out of the catheter body. Finally, during withdrawal of the catheter, the image-transmitting fiber and the tool would be within the catheter body. Accordingly, it is necessary for the physician to change the position of these components a multiplicity of times during the procedure. Unfortunately, prior art instruments of this type do not facilitate the positioning of these members to the extent desired.